Instrument measuring kinetic energy of particles - includes variable magnetic field between particle source and detector to slow down particles, and counts detected particles

摘要

The Kinetic energy of slowly moving charged particles is measured by counting the numbers of particles from a source (12) which reach a detector (10) when various different strengths of magnetic field are applied to the propagation path. The strength also differs along the propagation path, being stronger nearer the source. The magnetic field has a braking effect on the particles causing them to follow a spiral path, and the lower the Kinetic energy, the less likely the particle is to reach the detector. The source consists of a coil (17) and a magnetic circuit (10) consisting of four poles (13,14,15,16), reduced in volume at the centre to provide saturation. The path field is provided by a winding (19).